Some Micro Electrical Mechanical Systems (“MEMS”) comprise devices that are protected with lids. These lids may protect the MEMS devices from physical damage or interference. They may also, in conjunction with a substrate, provide other mechanical, optical, radiative, or fluidic functions. These lids present various problems, however.
Referring to FIG. 1, a MEMS chip 100 with a lid 102 has a bond ring 104 and electrical contacts 106. The lid covers a protected device 108 of the MEMS. One of the problems with a lidded MEMS is that it is typically larger than a MEMS without a lid. This is partly because the electrical contacts are separated by a distance D1 from the bond ring (and a corresponding distance from the protected device 108). This distance D1 is usually needed in order to permit electrical communication with the electrical contacts, in this case with a wire 110 applied with a bonder tip 112.
To partially reduce the size of the lidded MEMS, smaller bonder tips have been used. These smaller bonder tips permit a reduction in this distance but may cause other problems. They are often less reliable, which can result in unusable MEMS when they fail to electrically connect the wire to the electrical contacts. Also, the smaller bonder tips are usually less durable because of their smaller size, and so have to be replaced more often.
Another problem with lidded MEMS is that they can be expensive to test. MEMS, lidded or not, are often formed in large groups on a single substrate 114. MEMS without lids are typically tested with a probe card using an e-testing or parametric testing machine. MEMS with lids are not typically tested with a probe card, however, because the lids interfere with the probe card. For this reason, most lidded MEMS are first separated into individual, stand-alone devices. Each is then tested. Testing each lidded MEMS individually, however, is typically more expensive than testing a group of non-lidded MEMS with a probe card.
The same numbers are used throughout the disclosure and figures to reference like components and features.